According to SparkNotes, John Proctor is put to the test in Act III of “The Crucible” when he decides to confess to his affair with ringleader Abigail Williams. He cries, “God is dead!” after being falsely accused of witchcraft, to demonstrate that if he is accused of witchcraft, there must not be a God.
Prior to the witchcraft charges, John Proctor was regarded as a pure and moral man in the Salem community. When he cheats on his wife with their servant girl, Abigail, he falls from favour. He ultimately tells his wife, but he keeps his secret hidden from the rest of the world. When Abigail accuses Elizabeth of witchcraft, John determines that he must confess to the affair in order to prove that Abigail is not as angelic and trustworthy as the town’s judges believe. Mary Warren is terrified of Abigail and turns on Proctor after Elizabeth lies and says she believes there was an affair because she believes it will protect her husband’s good name. John is accused of being a witch by Warren. Because the judges trust Mary Warren and Abigail over John Proctor, John exclaims, “God is dead!” to demonstrate that anybody can be hanged for this unseen crime if an upright man like himself is accused of witchcraft. As a result, Salem is devoid of both justice and God.